陶瓷过滤器在振荡流场作用下脉冲反吹机理研究

The rigid ceramic filters is the key to the success of the advanced coal-fired power generation systems like pressurized fluidized bed combustion (PFBC) and integrated gasification combined cycle (IGCC) process. They meet downstream system component protection and environmental standards. In the commercial utilization of rigid ceramic filters, the performance of pulse cleaning systems has crucial effects on the long-term structural durability . The project is carried out to get a clear insight into the nature of enhancement of pulse cleaning process of dust cake at the action of self-oscillation flowfield. On the basis the experimental measurement of self-oscillating flowfield, a kind of new-type self-oscillaing pulse nozzle is optimized and a kind of pulse cleaning injetor is invented. The comparaton test show that the kind of pulse gas injector can markedly improve the cleaning efficiency and . the transient flow characteristics of the rigid ceramic candle filter during the whole pulse cleaning process should be completely analyzed. In this work, on the basis of experimental results, the flow in the pulse-jet space and inside ceramic candle is regarded as two-dimensional, unsteady, compressible and axisymmetrical flow. The flow procedure can be used to calculate the transient flowfield in ceramic candle and analyze the effects of operation and geometry parameters on the pulse cleaning performance of the ceramic filter. By using laser optical system and high speed CCD camera, the breakup process of dust cake shows that there exists incomplete removal of cake from the filter candle along the axial direction. The cake formation model given in the project can be used to simulate the two-dimensional build-up and the microstructure of a dust cake during filtration. The dynamic model of pulse cleaning system, consisting of pulse gas reservoir, nozzle, solenoid valve and connecting pipelines, has been proposed and derived on the basis of flow transients theory and gas thermodynamics. The modeling results of mass flow rate are consistent with the experimental data obtained by using hot-wire anemometer. It is shown that the dynamic model can be well applied to optimize and design the pulse cleaning system of pilot plants.

研究由流体自激振荡型脉冲反吹喷嘴产生的振荡流场的频率及幅值特性，以设计新型脉冲反吹喷嘴，然后研究振荡流场对脉冲反吹清灰效率与沿滤管清灰均匀性的强化作用。在实验研究基础上，运用气固两相流理论，建立全新的脉冲反吹清灰模型，对于发展刚性陶瓷过滤理论，开发洁净煤燃烧发电用高温陶瓷过滤器用新型脉冲反吹技术具有重要意义。